Panniers are frequently attached to the rear of motorcycles for the storage and transport of goods, however at higher speeds it is common for the addition of panniers to affect the stability of a motorcycle. This instability manifests in a wobble which is experienced in the steering of the vehicle and feeds back to the rider via the handlebars and leads to steering instability.
Traditionally the instability caused by the addition of panniers is alleviated by changing the chassis geometry which generally gives a reduction in motorcycle agility as perceived by the rider.
Generally, adding mass behind the centre of gravity of a motorcycle increases a susceptibility to instability caused by energy input into the bike, for example by buffeting of the panniers which present a different cross section to a bike with no panniers, or for example from bumps in the road surface. In order to minimise the speed effect of panniers upon a motorcycles steering stability there has been a move by some manufacturers from very rigidly mounted panniers to panniers that are mounted with some flexibility within the pannier mounting system so that they are not too rigidly connected to the frame or panels of the bike. This allows them some pannier movement, which may assist in minimising the effect of any energy input on the stability of the bike.